[1] [CITE@en-US[Touch.radiusX - Web API interfaces | MDN]]
( ([TIME[2013-09-30 12:59:44 +09:00]] 版))
<https://developer.mozilla.org/en-US/docs/Web/API/Touch.radiusX>

[2] [CITE@en[Touch Events Extensions]]
( ([TIME[2013-10-29 05:03:47 +09:00]] 版))
<http://www.w3.org/TR/2013/NOTE-touch-events-extensions-20131031/#widl-Touch-radiusX>